A study done at Loyola Medicine and Loyola University Chicago and published in the journal International Urology and Nephrology found 19 types of bacteria in the urine of patients with kidney disease. Staphylococcus, Streptococcus, Corynebacterium, Lactobacillus, Gardnerella, Prevotella, Escherichia, Shigella and Enterbacteriaceae were some of the bacteria found. Interestingly few samples were overpoweringly dominated by a single genus. Even samples that had one dominant type of bacteria also contained several other major types.
Doctors are trained to believe that urine is sterile. A study done at Loyola earlier disproved this common belief and this new study has expanded on that earlier finding.
Bacterial diversity was generally higher among patients with urine urgency. Generally, urine in healthy patients has one or two dominating bacteria yet in kidney disease patients researchers found many different types of bacteria. This finding supports previous findings that proved that microbiome diversity tends to influence a person’s health. For example, low gut microbiome diversity is linked to inflammatory bowel syndrome and high vaginal microbiome diversity is associated with vaginal infection.
The researchers studied the urine of 36 men and 41 women who had Stage 3 to Stage 5 kidney disease though not on dialysis. Of the study participants:
- All were at least 60 years old.
- All had less than 60% kidney function and the average kidney function was 27%.
- 69% of the men and 70% of the women had diabetes.
- 42% of the men and 51% of the women had urinary urgency.
- 78% of the men and 51% of the women had excessive nighttime urination.
Healthy kidneys are known to secrete antimicrobial peptides in urine, preventing infections and kidney stones. The researchers suspect that people with kidney disease probably secrete fewer peptides and that leads to a more diverse microbiome.
The departments of nephrology, urology, microbiology and public health all collaborated in the study and the sequencing and analysis of the bacterial DNA were done by the Loyola Genomics Facility.